Terminal-antenna device for moving satellite constellation

Abstract

A terminal and antenna system ( 1, 10 ) for transmitting and receiving radio signals to and from satellites ( 2, 3 ) chosen from a constellation of non-geostationary satellites, including means for determining the position of the satellites visible from the terminal and antenna system, means for focusing quasi-plane waves received from or transmitted to a chosen visible satellite towards a focal surface S, primary sources ( 23, 24 ) for transmitting and receiving signals in the form of quasi-spherical wave beams, mobile independently over the sphere S in a manner that is slaved to the particular position of the non-geostationary satellites.

What is claimed is:  
     
       1. An antenna system for transmitting and receiving radio signals to and from a remote transceiver system moving in space visible from said antenna, said antenna system comprising: 
       a first lens for focusing quasi-plane waves emitted by said remote transceiver system, said lens having a focal sphere S;  
       at least one primary source for transmitting and receiving signals in a form of quasi-spherical wave beams, mobile on a portion of the sphere S; and  
       a second lens for deflecting the quasi-plane waves transmitted or received by the remote transceiver system,  
       wherein a position of said at least one primary source for transmitting and receiving signals is assigned to a position of the remote transceiver system.  
     
     
       2. A terminal and antenna system for transmitting and receiving radio signals to and from at least two remote transceiver systems at different points in space visible from said terminal and antenna system, said terminal and antenna system comprising: 
       a positioning system which determines position of said at least two remote transceiver systems in view at a given time;  
       a selector which chooses a remote transceiver;  
       an antenna system comprising:  
       a first lens for focusing quasi-plane waves emitted by the remote transceiver, said lens having a focal sphere S,  
       at least two primary sources for transmitting and receiving signals in a form of quasi-spherical wave beams, mobile on a portion of the sphere S, and  
       a second lens for deflecting the quasi-plane waves transmitted or received by the remote transceiver;  
       a controller which controls movement of the at least two primary sources for transmitting and receiving signals over the focal sphere S adapted to prevent the at least two primary sources for transmitting and receiving signals from colliding, and  
       a switch for switching between the at least two primary sources for transmitting and receiving signals.  
     
     
       3. A system according to claim  2 , further comprising a data recovery system which recovers data lost during the switching. 
     
     
       4. A system according to any of claims  1  or  2 , wherein at least one primary source for transmitting and receiving signals is a horn antenna mobile on a portion of the focal sphere S of the first lens for focusing the quasi-spherical beams into quasi-plane beams. 
     
     
       5. A system according to any of claims  1  or  2 , wherein at least one primary source for transmitting and receiving signals comprises a module for amplifying the transmitted and received signals. 
     
     
       6. A system according to any of claims  1  or  2 , wherein the first lens for focusing quasi-plane waves into quasi-spherical waves is a multifocal convergent lens having a wide scanning range. 
     
     
       7. A system according to claim  6 , wherein the scanning range is made greater than 30° relative to the axis of symmetry of revolution of the first lens by moving at least one primary source for transmitting and receiving signals over the focal sphere S. 
     
     
       8. A system according to claim  6 , wherein the first lens is a convex dielectric lens. 
     
     
       9. A system according to claim  6 , wherein the first lens is a concave waveguide lens. 
     
     
       10. A system according to claim  6 , wherein the first lens is zoned. 
     
     
       11. A system according to claims  1  or  2 , wherein the second lens for deflecting the quasi-plane waves is a dielectric dome lens. 
     
     
       12. A system according to claim  11 , wherein the second lens has a generally hemispherical overall profile. 
     
     
       13. A system according to claim  11 , wherein the second lens has generally parabolic, elliptical or hyperbolic inside and outside profiles. 
     
     
       14. A system according to claim  11 , wherein the second lens increases in thickness from a summit thereof to a base thereof. 
     
     
       15. A system according to claims  1  or  2 , wherein the second lens is disposed so as to isolate the system from the external environment. 
     
     
       16. A system according to claims  1  or  2 , wherein at least one of the first and second lenses comprises a quarter-wave matching layer. 
     
     
       17. A system according to claim  16 , wherein the quarter-wave matching layer comprises a dielectric material having an index equal to the square root of an index of a dielectric material of the at least one of the first and second lenses. 
     
     
       18. A system according to claim  16 , wherein a thickness of the quarter-wave matching layer is equal to one quarter of a wavelength used and the quarter-wave matching layer is pierced with a plurality of blind holes with a density of piercing adapted to create an equivalent index equal to the square root of an index of a dielectric material of the at least one of the first and second lenses. 
     
     
       19. A system according to claim  2 , wherein the remote transceiver systems are satellites of a constellation and the positioning system determines the position at a given time of the satellites in sight, the positioning system comprising: 
       a database of orbital parameters of each of the satellites at a given time,  
       a storage system which stores terrestrial position parameters for the terminal and antenna system,  
       software for calculating a current position of each of the satellites from initial orbital parameters and a time which has elapsed since an initial time, and  
       software for comparing an orbital position with an angular area visible from a position of the terminal and antenna system,  
       wherein the database of the orbital parameters is regularly updated.  
     
     
       20. A system according to claims  1  or  2 , wherein at least one primary source for transmitting and receiving signals comprises a detector which detects a pointing error relative to a beam received from a moving remote transceiver. 
     
     
       21. A system according to claims  1  or  2 , wherein, to move at least one primary source for transmitting and receiving signals over at least a lower half of the focal sphere, the at least one primary source for transmitting and receiving signals is mounted on a support and is moved by at least one pair of motors. 
     
     
       22. A system according to claims  1  or  2 , wherein an assembly comprising first and the second lenses is mounted on a support separate from at least one primary source for transmitting and receiving signals, the system further comprising a motor for driving the support of said assembly so that said assembly extends substantially parallel to the beams. 
     
     
       23. A system according to claims  1  or  2 , wherein at least one primary source for transmitting and receiving signals is moved by a pair of azimuth and elevation motors. 
     
     
       24. A system according to claim  23 , further comprising a support for at least one primary source for transmitting and receiving signals, said support comprises a swing on which the at least one primary source for transmitting and receiving signals is fixedly mounted, the swing being moved along an axis by an azimuth motor of the pair of motors and moved relative to a vertical by an elevation motor of the pair of motors. 
     
     
       25. A system according to claim  23 , further comprising a support for at least one primary source for transmitting and receiving signals, said support comprises an arm forming a circular arc concentric with the focal sphere, positioned on a respective half of a lower part of the focal sphere, the arm being rendered mobile in azimuth by an azimuth motor of the pair of motors, and the at least one primary source for transmitting and receiving signals being rendered mobile along the arc by an elevation motor of the pair of motors. 
     
     
       26. A system according to claims  1  or  2 , further comprising a pair of X and Y motors, a first motor of said pair of motors rotating at least one primary source for transmitting and receiving signals about a horizontal primary axis Ox, and a second motor of said pair of motors rotating at least one primary source for transmitting and receiving signals about a secondary axis Oy orthogonal to said primary axis at all times and moved relative to the primary axis by the first motor. 
     
     
       27. A system according to claim  2 , further comprising: 
       a pair of azimuth and elevation motors; and  
       a pair of X and Y motors,  
       wherein a first primary source of said at least two primary sources for transmitting and receiving signals is moved by the pair of azimuth and elevation motors, and a second primary source of said at least two primary sources for transmitting and receiving signals is moved by a pair of X and Y motors, an azimuth motor of the pair of azimuth and elevation motors of the first primary source also driving the antenna as a whole.  
     
     
       28. A system according to claims  1  or  2 , wherein at least one primary source for transmitting and receiving signals is moved by a pair of motors with oblique rotation axes. 
     
     
       29. A system according to claim  28 , further comprising a support for at least one primary source for transmitting and receiving signals, said support comprising an arm and a forearm, 
       wherein the at least one primary source for transmitting and receiving signals is fixed to a free end of the forearm,  
       a first motor of the pair of motors drives the arm in rotation about an oblique primary axis of the oblique rotation axis offset with respect to a vertical at a primary angle,  
       a second motor of the pair of motors drives the forearm in rotation relative to the arm about an oblique secondary axis of the oblique rotation axis offset with respect to the vertical at a secondary angle greater than the primary angle, and the primary and secondary axes are on respective opposite sides of the vertical.